Punch



Dec. 19, 1933. STOWELL 1,940,438

PUNCH Filed July 28, 1931 IIIIIIIIIA wi l atentecl Dec. 19, 1933 a f 9 AUNITEDSTATES PATENT OFFICE PUNCH Austin L. Stowell, New Britain, Conn., assignor to The Stanley Works, New Britain, Conn., a corporation of Connecticut Application July 28, 1931. Serial No. 553,499

4 Claims. (01. 164-124) This invention relates to a punch, such as cutting edge of the punch, the slug in the cutused by shoemakers andthe like, for forming ting operation being somewhat compressed and holes or openings in sheet material, such as forced into the chamfered portion 12. There is leather. no tendency to stretch or enlarge the hole, as

. 5 The-aim of the inventionis to provide a punch would be the case if the punch had an external 5 of this sort having various features of novelty chainfer terminating in a cutting edge.

and advantage and which is particularly charac- For the purpose of ejecting the slugs or disks terized by its effectiveness in operation and its after they are cut from the material, a spring simplicity in construction. pressed plunger B is provided. This plunger More particularly, an aim of the invention is has a head 13 fitting loosely in the forward end 65 to provide a punch, the cutting edge of which is of the bore 10, and a rearwardly extending stem so disposed and constructed that, during the op- 14. Within the bore 10 is a spring C, the rear eration of forming a hole, the material about end of which bottoms against the inner end of the hole is not unduly stretched or deformed. the bore and the forward end of which engages v15 A further object of the invention is to provide against the rear shoulder of the head 13. The 70 a punch with a plunger for ejecting the slug or stem 14 adjacent the head 13, has an annular portion cut from the material, the plunger being groove 15, and the foremost turn or convolution associated with the body portion of the punch 16 of the spring C is somewhat contracted so in a very simple and effective manner, the arthat it engages in this groove, and thus acci- 20 rangement being such that the structure may be dental separation between the spring and the 75 very economically manufactured as it comprises plunger is prevented. The body portion of the but arelatively few number of parts, each simple spring fits loosely in the bore 10 so that it is in itself, and which parts may be readily asfree to contract and expand, but the rearmost sembled. coil or convolution 17 of the spring is normally Other objects will be in part obvious and in of greater diameter than that of the bore so 80 part pointed out more in detail hereinafter. that, when the spring is inserted into the bore,

The invention accordingly consists in the fe the end convolution is somewhat compressed tures of construction, combination of elements due to its tendenfiy t0 eXiOand radially, this and arrangement of parts which will be exemconvolution will exert sufficient frictional force plified in the construction hereinafter set forth again h W ll f r to p v the spring 35 ti may t k a spring from the punch body. This can be done and the scope of the application of which will be and plu fIOIn accidentally Coming Out Of indicated in the appended claims, the bore. The forward end of the plunger may In the accompanying drawing, wherein i have a small threaded recess 18, the purpose of shown one embodiment which the present inven- Which is to facilitate removal of the plunger and 0 Figure 1 is a perspective view f the complete by merely screwing a threaded stem into the structure; recess and then pulling outwardly on the stem. Fig. 2 is a side view thereof, the forward end 7 It w be seen from the foregoing rip i n. of the punch being a central longitudinal sectak n n connection with t a pa ng tion; and. drawing, that my improved arrangement is an Fig. 3 is a side elevational view of the plunger extremely Simple 0116 making f cono y in per se. manufacture. The device comprises but three Referring to the drawing in detail, A desigparts, namely t body, the plunger d t nates generally the body portion of the punch prin and ch of these p r s may be made 45 which is preferably in the form of a round bar a a a v y w e pa ay b V y or cylinder having a longitudinal bore 10 in its ly and q i y assembled, it being pp ren forward end. The extreme forward end of the that the spr ng may be e ed W the p e punch body terminates in a cutting edge 11, by merely reducing the diameter of the forward which is preferably formed by internally chamend of the spring so that it Will fi in the groove 5o fering the forward end of the punch body, as e P 3 and Spring a e assembled at 12. The external wall of the cutting edge is within the bore by merely bringing the rear end substantially cylindrical, while the internal wall of the spring into the chamfered end 12 and thereof is tapered inwardly. With this arrangethen pushing backwardly on the plunger, ment, when a hole is punched in the material, thereby causing the rearmost convolution 1'7 to 55 the hole will be made the exact size as the contract. No separate means are necessary for holding the spring and plunger in place, as the radial pressure of the end convolution 17 against the wall of the bore is sufiicient to perform this function.

As many changes could be made in the above construction, and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

What is claimed is:

1. In a punch, a body member having a cutting edge and a bore at one end, a plunger at the forward end of said bore, and a spring in said bore and connected to said plunger, the inner end of said spring being contracted into said bore when inserted therein whereby said end of the spring will exert sufiicient frictional force against the wall of the bore to prevent accidental displacement of the spring.

2. In a punch, a body member having a cutting edge and a bore at one end, a plunger in the forward end of said bore, and a coiled spring behind said plunger and within said bore, the

forward end of said spring being connected to said plunger and the inner end of said spring being normally of greater diameter than that of the bore so that when the spring is inserted into the bore the rear end thereof is contracted and caused to bear frictionally against the bore wall.

3, In a punch, a body member having a longitudinal bore and a cutting edge at one end, a plunger in the forward end of said bore and having a rearwardly extending stem provided -with a circumferential groove, and a coiled spring in said bore behind said plunger, the forward end of said spring being engaged in said groove whereby to connect the spring and plunger together, the rear end of said spring being normally of greater diameter than the diameter of the bore.

4. In a punch, a body member having a longitudinal bore and a cutting edge at one end, a plunger in the forward end of said bore and having a head and a rearwardly extending stem, said stem adjacent said head being provided with a circumferential groove, and said head having a threaded recess, and a coiled spring in said bore behind said plunger, the forward end of said spring being engaged in said groove whereby to connect the spring and plunger together; the rear end of said spring being normally of greater diameter than the diameter of the bore.

AUSTIN L. STOWELL. 

